Our daughter used it from birth until 18 months. She has taken countless naps in it, both in the car and on the stroller, as well as at home after a car ride or on an airplane! We bought it because of its good price-to-performance ratio in the Adac crash test without a base.
It is very easy to install and remove in the car - it takes less than 1 minute if you know how to do it, and it fits comfortably in the car. It is quite heavy (there are lighter child seats by almost 1.5 kilograms), which makes it difficult for my pregnant wife - essentially, she couldn't carry the child and the seat together, but that doesn't mean she couldn't move it if it didn't have that extra 1.5 kilograms.
Putting the child in the car with the seatbelt - without the isofix base - was not the easiest because you have to pass its legs under the belt (impossible with shoes), which can be an issue if the child is fussy. The solution is to remove the belt, put the child in comfortably, buckle it, and then buckle the seat to the belt. I don't think there is a seat that can be buckled with a belt without the above.
It fit well on our stroller with adapters.
Countless naps, both at a younger age and until now, without any complaints, but clearly the head falls forward, especially as the child grows and sits more upright.
The canopy is very good, the materials are very good, and the fastening is very good.
The summer cover is very expensive at 50 euros, but necessary because otherwise the child gets too hot - as with all child seats, really.
Overall, no complaints or unexpected issues other than the weight, which we knew from the beginning.
Our plan was to try it without the isofix base, and if we had any issues, we would get a second one for the other car because at 130 euros, the base was an additional 130 euros, which was not justified.
Now that the child has moved to a 360-degree seat with an isofix base, which can turn to the side, it is obviously much easier to install and remove since you don't have to maneuver and you don't have the obstacle of the restraining belt over the legs. In terms of comfort, however, as much as she cried in the previous seat, she cries in the 360-degree seat, and as much as she slept before, she still sleeps the same.
In conclusion, it is very safe at a very good price and much more comfortable, but above all, much safer than a package of seat and stroller.
Note: Our daughter is between the 50th and 75th percentile in height and between the 25th and 50th percentile in weight, so she is a normal to tall but thin baby, which affects how she fit and still fits in the seat.